QoS control for a wireless section in a mobile communication system, such as a digital portable telephone system and a PHS system, is implemented by a data link layer (a MAC layer) in the OSI reference model. Here, QoS (Quality of Service) is a function of setting a priority (service priority) for each communication in the network, thereby guaranteeing transmission quality.
In a case where an attempt is made to implement QoS control in a wireless section in such a mobile communication system, for instance, when down-link (a down line) data reached the MAC layer in IPv4, an IP header has already been removed, and therefore control utilizing a TOS field of the IP header cannot be performed.
Therefore, negotiations for service priority are conducted in the course of connection of a call from a terminal, and QoS control is performed for each wireless link.
Incidentally, when a multiservice (also called a multi-call), which corresponds to a plurality of services, is introduced for one user in a next-generation mobile communication system, a mixture of services of different service priorities is conceivable. For instance, a conceivable case is a mixture of VoIP (Voice Over IP) (for instance, a service with the highest service priority) for transmitting and receiving audio data by converting it into an IP packet and an electronic mail (e-mail) (for example, a service with the lowest service priority), and the like.
Patent Document 1 shows a method for managing a plurality of independent simultaneous calls between a mobile communication network and a subscriber terminal.
Patent Document 1: JP-T-2002-525934 (the term “JP-T” as used herein means a published translation of a PCT patent application)